Heat engines, such as steam engines, have long been used for converting heat energy into mechanical output. For example, Worthington steam pumping engines, for example as described in “The Worthington Steam Pumping Engine: History of its Invention and Development,” by H. R. Worthington, New York, 1887, may utilize a steam-driven piston for pumping water. Other reciprocating engines are also known for producing pumping action of pistons using steam power, for example as described in “Practical Handbook on Direct-Acting Pumping Engine and Steam Pump Construction,” by P. R. Bjorling, London and New York, 1889. Such pumps typically pump water via pumping, action of a piston by pushing water out of a cylinder, the piston driven by a steam-driven piston. However, reciprocating steam pumps based on these designs are often heavy, inefficient and costly, and ill adapted for performing forms of work other than the pumping of liquids.
Another type of steam engine is a steam-driven turbine, which may be used for extracting power from superheated steam. However, turbines typically require dry, and generally superheated steam, provided to the turbine under precisely controlled conditions. These constraints limit their usefulness, for example in systems where only wet saturated steam is available, or where the steam supply is irregular.
A number of other steam engines have been developed in recent years, which attempt to efficiently generate rotary motion from wet saturated steam. However, many of these are not well adapted to the production of electricity, given the torque and rotational speeds required of a generator for efficient electricity generation.
The uses of low and medium pressure saturated steam are largely limited to space and water heating. These uses fail to exploit the full potential of such steam for producing useful power. For example, residual heat from industrial processes is typically used for heating purposes, rather than for providing mechanical or electrical power.
Therefore there is a need for a new device and system that can extract desired useful work from pressurized gas such as wet saturated steam.
A number of systems have also been developed in recent years composed of turbines driven by the vapour of a low-boiling point (LBP) working fluid (“Organic Rankine cycle turbines”). These systems are capable of extracting useful work from a heat source of relatively low temperature. However, they are subject to the same constraints as other turbines, and as a result their capital and operating costs are often too high for many applications.
There is thus also a need for a new device and system that can extract useful work from relatively low-temperature heat sources, without the costs and operational constraints associated with Organic Rankine Cycle turbines.
This background information is provided to reveal information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.